Machines for filling liquid into containers (fillers), such as bottles and/or cans, are known which include a rotating assembly having a plurality of filling stations each of which receives a single container. Each bottle is initially received on a base which, as the assembly rotates, is moved upward so that a vent tube extending downward from the filling station is received in the bottle. This vent tube serves several purposes. First, the vent tube aids in centering the bottle so that it is received in the filling station in a desired orientation. In addition, as liquid is filled, the vent tube vents gas from the bottle, sets the height to which liquid is filled in the bottle and modifies the flow pattern of the liquid being filled into the bottle.
To achieve these goals, known vent tubes have included a central hollow tube extending from a lower, tapered, fill tip upward to a filling valve. Between the filling valve and the fill tip, a spreader in the form of a projecting disc extends from the outside of the vent tube to divert the flow path of liquid flowing down the outside of the vent tube so that the liquid flows down the sides of the bottle. This allows much higher filling speeds than could be obtained if the liquid were filled straight into the bottle.
However, increased filling speeds have increased the severity and frequency of problems caused when the bottles improperly receive the vent tubes. If on entering the filling station, the bottle is misaligned with respect to the vent tube, contact between the bottle neck and the spreader can cause the bottle to be crushed as the base raises the bottle toward the filling valve. This can cause jams which, at high speeds, can result in jams which require that the production line be shut down, decreasing efficiency and requiring the services of one or more technicians to remedy the problem. In addition, such jams can result in the destruction of the filling valve at the effected filling station. This valve, which is an expensive part, must then be replaced. Replacing the valve is difficult and time consuming and requires the emptying of the liquid from the filler, further increasing the costs associated with the jam.
Alternatively, contact between the spreader and the bottle can result in damage to the upper surface of the bottle neck. This can impair the sealing of the bottle causing problems such as, for example, loss of carbonation of the product. This, in turn, results in a decrease in the shelf-life of the product.
In order to reduce contact between bottles and the spreader, a vent tube 10, as shown in FIG. 1, is known in which the fill tip 12 has been extended outward so that a maximum diameter of the fill tip 12 is equal to or greater than a maximum diameter of the spreader 14. However, although this fill tip 12 has reduced problems associated with contact between the bottle and the spreader 14, a new problem has arisen in the filling of carbonated products. Due to the increased diameter, a vacuum is drawn when the fill tip 12 is removed through the neck of the bottle, adversely effecting the carbonation of the product, thereby decreasing product shelf life.
As shown in FIG. 2A, a vent tube 10' is known which includes a bottle guide 20 positioned between the fill tip 12 and the spreader 14. The diameter of the bottle guide 20 gradually increases from a minimum diameter at the lowermost portion thereof to a maximum diameter after which the diameter decreases to the diameter of the vent tube 10'. The portion of the vent tube 10' above the bottle guide 20 includes a threaded portion 22 with a first locking nut 24 received below the spreader 14 and a second locking nut 24' positioned above the spreader 14 on a second threaded portion 23. The locking nuts 24 and 24' maintain the spreader 14 in a desired position and allow this position to be adjusted by moving the locking nuts up or down on the threaded portion 22. Similarly, locking nut 21 is received on a third threaded portion 27 above for adjusting the position of the fill tip 12, while locking nuts 25 and 25' are received on threaded portions 27 and 22, respectively for adjusting the position of the bottle guide 20. Thus, such vent tubes 10' may be adapted for use with various bottle sizes and shapes by moving the spreader 14, the bottle guide 20 and the fill tip 12 to desired locations relative one another and to the filling valve.
However, adjusting the height of the spreader 14 requires that an operator grip one of the locking nuts 24, 24' by inserting a tool over the locking nut and rotating the locking nut until the spreader 14 has reached the desired position. The other locking nut is then rotated to tighten the spreader 14 in the desired position. However, this operation can loosen the vent tube 10' which is screwed into the filling station at the threaded portion 29. This can require further tightening of the vent tube using a tool to turn one of the locking nuts which may move the spreader 14 out of the desired position. The position of the spreader 14 is critical to filling efficiency and differences in the height of the spreader 14 of 1/16" or less can adversely effect the filling speed. Thus, this type of vent tube 10' is susceptible to improper vent tube positioning, reducing efficiency and requires a significant effort on the part of the technician to replace and/or adjust the tubes to adapt a filler to accept a new size or shape of bottle. Similarly, improper positioning of the fill tip and the consequent inaccuracy of the fill height may lead to consumer complaints and may also result in violations of consumer protection laws.
Finally as shown in FIG. 2B, a vent tube 10" similar in shape to the vent tube 10' is known which has addressed the problems associated with the adjustable height spreader tubes 10' by including an open tip 11, bottle guide 20 and spreader 14 integrally formed with the vent tube. This vent tube is snap fit into the filling station eliminating the need to use tools to tighten the vent tube into the filling station and ensuring proper spreader placement. Thus, instead of adjusting the relative position of the spreader and the fill tip to accommodate different bottle sizes and shapes, users of this vent tube simply exchange the old vent tubes for a new set specifically adapted for the new type of bottle.
However, both the vent tube 10' and the above-described vent tube with the integrally formed spreader suffer from all of the problems associated with contact between the bottle and the spreader 14. The bottle guide 20 reduced but has not eliminated these problems. Especially at higher filling speeds (up to 1,000 bottles a minute), these problems persist and the resulting jams are more serious and costly. Specifically, when a bottle enters a filling station out of the proper alignment, the neck of the bottle may slide past the bottle guide 20 to abut the under side of the spreader 14. Then, as the bottle is raised through the camming action of the filler, the neck of the bottle may be crushed. This crushed bottle will likely cause a jam--for example, during transfer from the filler to the next processing station.